What are the keywords in the following sentence? The couch in this room is covered with a sheet. 
couch, cover, room

What are the keywords in the following sentence? A room filled with furniture and paintings on the wall.
fill, furniture, painting, room, wall

What are the keywords in the following sentence? He enters the living room, smiling.
enter, room, smile

What are the keywords in the following sentence? waiting room at underground station

room, station, wait